The present invention relates to a solid state laser device for a lithography light source and a semiconductor lithography method.
As a high degree of integration of ICs is increasing and manufacturing processes for ICs become complicated, a technological miracle is required for manufacturing a semiconductor device. The industries of semiconductor manufacturing devices are engaged in technical developments which see into the situation after 64 MDRAM as well as 16 megabit dynamic RAM (Hereinafter, it is called as MDRAM: Random Access Memory which needs storage holding operation.)
As semiconductor manufacturing devices, there are available an exposure device, an ion implantation device, an etching device, a CVD (Chemical Vapor Deposition) device, a sputterring device, an inspection device, an assembly device, and the like. Among them, it is a stepper (a successively moving type compact exposure device) that relates to the degree of integration of ICs and attracts attention. This is a device which prints patterns of electric circuits on a silicon wafer using a ray of light. How such fine lines can be drawn by the stepper is to directly determine the degree of integration of a memory and the like.
The lithography technology is a basic one for fineness of such a semiconductor device. Efforts for fineness are being promoted by various lithography technologies such as electron beam exposure, X-ray exposure, ion beam exposure, and the like, including light exposure.
Though the light source for lithography which is used as a leading one at present is a G ray (436 nm) of an extra-high voltage mercury lamp, a type using an I ray (365 nm) is announced. Further, a plan which copes with microscopic working in the future by use of a KrF excimer laser (wavelength is 248 nm) type stepper as light exposure is in progress.
When using the G ray (436 nm) and the I ray (365 nm), the degree of integration of ICs is limited by the restriction of the wavelength of the light source, and it is considered that the degree of integration up to 16 MDRAM is a limit. In order to further enhance the degree of integration, a short-wavelength excimer laser is nominated for the light source in the next generation, and research and development on it are promoted.
There are a lot of defective points when an excimer is introduced in its manufacturing line. Fluorine gas which has not been used in a conventional manufacturing plant is introduced. Since fluorine gas is a fairly dangerous gas, sufficient safety measures for gas piping materials, a piping system, and the like are required.
In addition, gas equipments are necessary as a peripheral device and it is considered that anti-dust and anti-noise measures (gas circulation equipment) are necessary while the device is made large-sized and the place for its installation is limited.